First start by placing the yellow raisins into a small bowl with the 2 tablespoons of brandy. Leave to soak whilst you prepare the other ingredients.
Scrub the potatoes and cook for 20 minutes or until semi-soft in boiling salted water. Drain away the water and dry the potatoes thoroughly -they should be nice and waxy. Slice horizontally into thin discs and place into a bowl. While still warm, add the melted butter and season to taste with a pinch of sea salt.
Into 6cm diameter bun cases or individual moulds, press the disks tightly inside and chill to set for at least 1 hour. Roll out the puff pastry to a thickness 0.5cm. Using a knife, run around the set potatoes to remove them from the mould. Along the centre of the puff pastry, place the set moulded potato circles with a few gaps between adding a few of the soaked sultanas on top. Brush egg wash on the outside edge of the pastry then seal by folding over the top with the opposite edge.
Using an 8cm round pastry cutter, form individual rounds around each set of potatoes. With a small 2cm pastry cutter, make a hole into the top each round. Push in the shaved chocolate and score lightly to make a creative pattern. Egg wash and sprinkle with a few pinches of sea salt. Set aside to rest and set the puffs. Pre-heat your oven to 240°C/gas mark 9. Once heated, bake the puffs for approximately 10 minutes. Remove from oven, and check the base is crisp and not soggy with a golden brown finish on top. Serve immediately.